The omission of bits in a data stream is called puncturing. The repetition of individual bits in a data stream is called repetitive coding.
It is known practice to perform puncturing or repetitive coding of data streams using puncturing or repetition masks, which are used to impress a fixed puncturing or repetition pattern onto a prescribed number of bits in a data stream per clock cycle. However, using such a rigid mask means that the puncturing or repetition pattern is unalterable, so that a new mask is required whenever the pattern is altered. Greater flexibility in terms of the variability of the puncturing and repetition patterns is provided by digital signal processors (DSPs). However, a pure software solution implemented on a digital signal processor requires a relatively high level of computation complexity, since a plurality of computation operations are necessary each time a bit is processed.
The application WO 01/05059 A1 discloses an apparatus for rate matching for data streams with a demultiplexer, parallel apparatuses for puncturing or repetitive coding, and also a multiplexer. The demultiplexer associates the various components contained in the incoming data stream (e.g data or check symbols) with the various parallel paths in the apparatus. Following rate matching for the component data streams in the individual paths by means of puncturing or repetitive coding using a fixed puncturing or repetition pattern, the bits are combined into a joint data stream again in the multiplexer.